In the US, incidence of cervical cancer in young whites is increasing and at the present rate will double in approximately 20 years, although Pap smear screening has intensified. Incidence in whites and minorities is approaching equality; in developing countries, cervical cancer is the most frequent cause of disease and death from malignant tumors. In the US, women with atypical smears are evaluated by colposcopic examination and, usually, tissue biopsy, placing large and expensive demands on medical resources. Abnormal Pap smears have a reported false negative rate of 20- 40%. colposcopic examinations also are subject to variability in training and experience of the gynecologist. Even experienced consultants can use a consistent objective measure as a staging aid. Reducing two-stage errors would substantially decrease human and financial costs. We aim to demonstrate that a low-cost, non-invasive, non-contacting, visible-light clinical instrument can optically differentiate cervical intraepethelial neoplasia from normal tissue and other abnormalities, including perhaps, invasive carcinoma. Differentiation based on depth- discriminated autofluorescence is known to be clinically significant in cervical dysplasia. The measuring instrument is interfaced with any standard colposcope and will not interfere with colposcopic examination. PROPOSED COMMERCIAL APPLICATION: The ColpoProbe will provide the physician with immediate in-vivo pathology, delineating abnormal cell regions during examination. The gynecologist can commence treatment, at the initial visit after a positive Pap smear, without waiting for the report of the laboratory pathologist. Instead of selecting a few specific sites for tissue biopsy, the whole region can be rapidly scanned. Follow up evaluation will be faster and could be done by a nurse practitioner. We forecast savings of about a $1,000 per patient. Location of residual cancerous cells in surgery is another important application.